Since the advent of compound bows decades ago, numerous variations have been made to the cord, pulley and cam systems to improve the mechanical advantages provided by the compound bows, such as greater arrow velocity and increased let-off weight. It is widely recognized that compound bows can shoot arrows with greater speed and energy for a given draw weight than conventional or recurve bows. Compound bows can be further advantageous by providing for ‘let-off’, which is the reduction in the force needed to pull back or restrain the bowstring as the shooter completes the draw back of the bowstring prior to releasing the arrow, as indicated by a percentage of the maximum draw weight. In theory, a let-off weight of 85% at the maximum draw length allows the shooter to maintain the bowstring in the fully-drawn position by only applying 15% of the maximum draw weight experienced during earlier portions of the draw pull.
While the compound bow's mechanical components can provide the user with significant advantages during use, these same components can also interact with the user, the environment, or with each other in ways that can introduce inaccuracies into the shooting system. In order for a compound bow to shoot true and straight, for instance, the upper and lower pulleys or cams must be synchronized together to provide a release force that is imparted evenly to both ends of the bowstring. However, normal wear and tear, thermal effects, improper maintenance, etc., can often throw the upper and lower components out of synchronization and alignment.
Likewise, improvements which may otherwise increase the exit velocity of the arrow as it leaves the compound bow may simultaneously torque or twist the cam assemblies mounted to the forked or slotted ends of the limbs, creating additional shooting errors. What is needed is an improved but simplified compound bow cam system which can simultaneously increase arrow speed while reducing the twisting effects on the cam assemblies that reduce accuracy and introduce unwanted noise and vibration.